The Taliban says it was behind the suicide attack near Camp Phoenix, on Kabul's outskirts. The casualties include military personnel and civilian contractors, but nationalities are not yet known.

A U.S soldier stands guard at the scene of a suicide bomb blast in Kabul. (Paula Bronstein / Getty…)

Reporting from Kabul, Afghanistan — The Taliban claimed responsibility for a suicide car bombing outside a major U.S. military base on the outskirts of the capital today that injured at least two dozen people, including nine Western troops.

The attack came on a busy road that connects Kabul with the eastern city of Jalalabad; it is heavily used by military vehicles and civilian cars alike, and Afghans have long complained of the danger to motorists who are caught up in insurgent attacks against Western forces. A bombing on the same stretch of road three months ago targeting a military convoy, killed eight people.

The North Atlantic Treaty Organization force said none of its troops was killed in today's bombing, but said those hurt included nine military personnel and 10 civilian contractors. After a series of seesawing casualty reports, Afghan authorities said at day's end that five civilians were injured.

The blast occurred about 8 a.m. close to the entrance to a logistics and support base known as Camp Phoenix, on Kabul's eastern edge. Most of the Western troops stationed there are Americans.

The attack was the first serious strike in the capital since the cancellation earlier this month of a runoff presidential election that had been set for last Saturday. The Taliban had threatened violence to disrupt that vote, which was called off when President Hamid Karzai's main opponent, former Foreign Minister Abdullah Abdullah, dropped out of contention. Karzai is to be inaugurated next Thursday.

The attack came as the Obama administration is conducting a top-level review of its strategy in the Afghan war. There have been growing signs of disagreement within the administration over whether to go along with a reported recommendation by U.S. Army Gen. Stanley A. McChrystal, the top Western commander in Afghanistan, to deploy an additional 40,000 troops.

The American ambassador to Afghanistan, Karl Eikenberry, a retired general who was previously commander in the Afghan theater, urged against such a large increase, according to cables whose contents were disclosed by officials in Washington. Eikenberry reportedly cited qualms over Karzai's reliability as an ally and the prospect of excessive Afghan dependency on the West.